Pic Collage is a useful app for the iPad that has now been developed for Windows 8.1 and 10. It is free but comes with a watermark when printed out. To remove the watermark it will cost £1.49 but worth it as the results are simple and effective. A great little edition to the world of photography and poster making. The range of thing you can do with this app using a touch enabled device is great from posters to advertise events to collages of your christmas party. I recommend you take a look through the windows store.